How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Cardoctor71 Your Own Question
Cardoctor71
Cardoctor71, ASE Master Technician
Category: Ford
Satisfied Customers: 670
Experience:  MasterCertified Technician with 35 years experience, Owner of two full service repair facilities
36867192
Type Your Ford Question Here...
Cardoctor71 is online now
A new question is answered every 9 seconds

What can cause gh negative fuel pressure on a E 450 ford

Customer Question

what can cause high negative fuel pressure on a E 450 ford super duty
Submitted: 1 year ago.
Category: Ford
Expert:  Cardoctor71 replied 1 year ago.

Please further explain high negative fuel pressure, so i can better assist you.

Customer: replied 1 year ago.
I got a check engine light on my 2005 Ford E450 motorhome with v10 engine, which turned out to be trouble code P0191. Fuel rail pressure sensor was replaced and light turned off. Engine runs fine but the light came back on. I noticed a small amount of negative pressure when unscrewing the gas cap. Replaced cap and then I noticed quite a bit of negative pressure with this cap when cap removed and engine is running. Light remains on and engine continues to operate normally. What can I do to keep solve this problem.
Expert:  Cardoctor71 replied 1 year ago.

Most likely you have an issue with the fuel vapor recovery system, particularly the evap/purge valve or charcoal canister.

Expert:  Cardoctor71 replied 1 year ago.

Please rate my service a 3 or above, if for some reason you can not, please ask me another question, I will continue to answer your questions even after you have given your rating until you are completely satisfied with my answers.